Modes of Operation

Protective mode

The native processor state (default mode, therefor most commonly used)

• Multiple processes can run but they are each given their own section of memory
• They are forced to stay within that section of memory and can't interact with other processes memory
• Every feature is available to you and you can do anything you want to do as long as you stay within the bounds of the memory

Real Address mode

Implements early intel programming environment with the ability to switch modes.

• Allows you to directly access hardware components

System Management mode

Provides an operating system with mechanisms such as power management and security.

• Useful when designing a system that's very specific to the processor